An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system

Eva-Maria Ladenburger, Iris Korn, Nicole Kasielke, Thomas Wassmer, Helmut Plattner

Research output: Contribution to journalArticle

Abstract

In the ciliate Paramecium, a variety of well characterized processes are regulated by Ca2+, e.g. exocytosis, endocytosis and ciliary beat. Therefore, among protozoa, Paramecium is considered a model organism for Ca2+ signaling, although the molecular identity of the channels responsible for the Ca2+ signals remains largely unknown. We have cloned - for the first time in a protozoan - the full sequence of the gene encoding
a putative inositol (1,4,5)-trisphosphate (Ins(1,4,5)P3) receptor from Paramecium tetraurelia cells showing molecular characteristics of higher eukaryotic cells. The homologously expressed Ins(1,4,5)P3-binding domain binds [3H]Ins(1,4,5)P3, whereas antibodies unexpectedly localize this protein to the osmoregulatory system. The level of Ins(1,4,5)P3-receptor expression was reduced, as shown on a transcriptional level and by immuno-staining, by decreasing the concentration
of extracellular Ca2+ (Paramecium cells rapidly adjust their Ca2+ level to that in the outside medium). Fluorochromes reveal spontaneous fluctuations in cytosolic Ca2+ levels along the osmoregulatory system and these signals change upon activation of caged Ins(1,4,5)P3. Considering the ongoing expulsion of substantial amounts of Ca2+ by the osmoregulatory system, we propose here that Ins(1,4,5)P3 receptors serve a new function, i.e. a latent, graded reflux of Ca2+ to fine-tune [Ca2+] homeostasis.

Original languageEnglish
Pages (from-to)3705-3717
Number of pages13
JournalJournal of Cell Science
Volume119
Issue number17
Early online date15 Aug 2006
DOIs
Publication statusPublished - 1 Sep 2006

Fingerprint

Paramecium
Paramecium tetraurelia
Inositol 1,4,5-Trisphosphate
Exocytosis
Eukaryotic Cells
Endocytosis
Fluorescent Dyes
Homeostasis
Staining and Labeling
Antibodies
Genes
Proteins

Bibliographical note

© The Company of Biologists Limited 2006

Keywords

  • Ca2+
  • IP3
  • calcium
  • inositol 1,4,5-trisphosphate
  • osmoregulation
  • paramecium

Cite this

Ladenburger, E-M., Korn, I., Kasielke, N., Wassmer, T., & Plattner, H. (2006). An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system. Journal of Cell Science, 119(17), 3705-3717. https://doi.org/10.1242/jcs.03075
Ladenburger, Eva-Maria ; Korn, Iris ; Kasielke, Nicole ; Wassmer, Thomas ; Plattner, Helmut. / An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system. In: Journal of Cell Science. 2006 ; Vol. 119, No. 17. pp. 3705-3717.
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Ladenburger, E-M, Korn, I, Kasielke, N, Wassmer, T & Plattner, H 2006, 'An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system', Journal of Cell Science, vol. 119, no. 17, pp. 3705-3717. https://doi.org/10.1242/jcs.03075

An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system. / Ladenburger, Eva-Maria; Korn, Iris; Kasielke, Nicole; Wassmer, Thomas; Plattner, Helmut.

In: Journal of Cell Science, Vol. 119, No. 17, 01.09.2006, p. 3705-3717.

Research output: Contribution to journalArticle

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AU - Ladenburger, Eva-Maria

AU - Korn, Iris

AU - Kasielke, Nicole

AU - Wassmer, Thomas

AU - Plattner, Helmut

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Ladenburger E-M, Korn I, Kasielke N, Wassmer T, Plattner H. An Ins(1,4,5)P3 receptor in Paramecium is associated with the osmoregulatory system. Journal of Cell Science. 2006 Sep 1;119(17):3705-3717. https://doi.org/10.1242/jcs.03075